My family traveled for 3 months in a motorhome, it was sort of a last gasp when we found out my dad was, well, about to shuffle off the mortal coil.
I remember seeing the grand canyon for the first time, I was 20' away from a moose in Yellowstone, timed ol' faithful, hiked in the badlands of South Dakota, was at the top of stone mountain in georgia, drove up big sur, I remember the smog in LA, the height of pikes peak, and the beauty of Zion. There is alot to see in the USA, we had one rule - KOA campgrounds only.
If I could go to one place it would be Crater Lake National Park. Actually Washington, Oregon, Idaho, and Alaska are the only states I haven't been to yet. Collect 'em all.